The invention relates to a machine for the pneumatic broadcasting of granular material, which has a central reservoir or hopper from which the material is delivered through a metering mechanism to a plurality of tubular conduits which are connected to a blower and discharge the material rearwardly through openings located on the body of the machine and at intervals along booms extending outwardly from either side of said body transversely of the direction of travel, the said booms being articulated to the body of the machine so as to be able to be raised against the body for travel over the road (transport position) or lowered for broadcasting the material (working position), the raising and lowering movement being limited by abutment means.
German "Auslegeschrift" No. 1,197,262 has disclosed a folding harrow frame in which the lateral arms are each divided into an inside section and an outside section, and all sections are articulated on horizontal axes parallel to the direction of travel, such that the bottoms of the outside sections are folded against the bottoms of the inside sections when the frame is in the transport position, thereby adding to the folded width of the frame. In this frame, too, there exists the disadvantage that damage can be done to the frame sections when they are in the working position if they encounter an obstruction or if the outside frame sections strike against the ground due to the rocking of the tractor pulling the harrow over uneven terrain.